Inertia-operated switch for conveyances and the like



Jan. 27, 1959 INERTIA-OPERATED SWITCH FOR CONVEYANCES AND THE LIKE J. PORCHEDDU 2,871,310

Filed Oct. 24, 1956 //[V///////A\V//////A7///A i! INVENTOR. Ja/zn Porch eadu BY M, We "M ATTORNEYS.

United States INERTIA-OPERATED SWITCH FOR CQNVEYANCES AND THE LIKE This invention relates to inertia-operated electrical switches, and more particularly to switches of this type, which are adapted for use in automobiles and other vehicles or conveyances.

With the increased incidence of selious accidents resulting from raised highway speeds, more powerful engines, the construction of expressways, thruways and parkway systems, it is becoming increasingly important to provide a reliable means by which the electrical circuits of an automobile or other conveyance will be automatically inactivated or deenergized upon the occurrence of a collision. In the past, proposals have been made to effect this by means of inertia-operated switches, to the end that there would be prevented the possibility of short circuits, hot or burning electric wires and the like, which could ignite spilled gasoline.

While certain prior proposals for effecting an opening of the electrical circuits have appeared to be feasible, they were characterized by either large or cumbersome structures, or a multiplicity of complex parts, or faulty or unreliable operation, or combinations of these factors.

An object of the present invention is to provide a novel and improved inertia-operated switch suitable for use in automobiles and similar vehicles, boats, aircraft and the like, which device is relatively small and compact, while at the same time being extremely eflicient and effective, and reliable in its operation.

Another object of the invention is to provide a novel and improved, inertia-actuated switch mechanism as above set forth, wherein relatively few components of simple construction are required, thereby reducing the manufacturing cost to a minimum.

Still another object of the invention is to provide an improved inertia-operated switch mechanism in accordance with the foregoing, which may be easily and quickly adjusted to provide the desired response, and which may be readily reset as occasion demands.

A feature of the invention resides in the provision of an improved inertia-actuated switch mechanism as above characterized, wherein large or heavy circuits may be readily broken, such circuits being of the type adapted to carry all of the-load normally involved in the operation of the conveyance.

Another feature of the invention resides in the provision of an improved switch mechanism as above characterized, wherein auxiliary switch means are provided by which an emergency light may be operated or energized, even though all the remainder of the electrical circuits have been inactivated or disconnected.

Other features and advantages will hereinafter appear.

In the drawings accompanying this specification, similar characters of reference indicate corresponding parts wherever possible in the several views, in which:

Figure 1 is a front elevational view of an improved inertia-responsive switch made in accordance with the invention.

Figure 2 is an axial vertical sectional view taken on line 22 of Figure l.

atent O 2,3213% Patented Jan. 27, 1959 Figure 3 is a bottom end view of the switch shown in Figures 1 and 2.

As shown, the improved switch mechanism of this invention comprises a generally flat, rectangular base 10 on which there are provided a pair of mounting plates 11 having upstanding bearing or guide portions 12 disposed in spaced, parallel relation to each other. The plates 11 and guide portions 12 may be advantageously constituted of angle iron or other angular structural forms, while the base 10 may be advantageously formed of laminated plastic or equivalent sheet insulating material.

In accordance with the present invention, disposed on the lower portion of the base 10 are two, novel angleshaped electrical contacts 14 and 15, said contacts having base portions 16 and 17 respectively, and upstanding, contacting portions 18 and 19 respectively. Preferably, the stationary contacts 14 and 15 are formed to have laminations, that is, to be made up each of two or more separate, angle-shaped members.

The contact portions 18 and 19 of the stationary contacts 14 and 15 are disposed broadside to each other in closely-spaced relationship, so as to accommodate between them a conducting, bridging member or switch blade 21 which is also preferably made in laminated form, as by folding over on itself a fiat strip to provide a double thickness.

As shown in Figures 1 and 3, the angle-shaped contacts 14 and 15 are secured to the base 10 by bolts 23 and 24 respectively, said bolts also constituting terminals by which electrical cables may be attached to the contacts.

Further, by the present invention, the laminated bridging member 21 is adapted toconstitute in effect an insulated or unconnected switch blade, having sufficient thickness that it tends to spread apart the contact portions 18 and 19 of the members 14 and 15 when in the circuitclosing position shown in the figures. Thus, the contacts 14 and 15 are bridged and effectively, electrically connected together, providing a low resistance, low heat path for even relatively large and heavy electric currents.

As shown in Figure 2, the bridging contact 21 is mounted for arcuate movement, being carried by an insulating disk or plate 26 to which the contact 21 is secured, as by rivets 27. The disk 26 bears on a spindle 28 carried by the guide portions 12 of the base plates 11, and spacer washers 30 are provided on the spindle, to centralize the disk 26 between said guide portions. Preferably the disk 26 is formed of a wear-resistant, insulating material, such as laminated phenolic composition or the like.

Referring to Figure 2, I provide a novel latch means comprising a shoulder 32 on the disk 26 and a movable locking member 33 having a cooperable shoulder 34 by which the disk 26 may be locked in switch-closing position and against clockwise turning movement, as shown and viewed in Figure 2. The locking member 33 is preferably in the form of short lever, being carried on a pin or spindle 35 passing through the guide portions 12, such member being biased counterclockwise by a helical compression spring 36 carried in a recess 37 in the base 10. Preferabl, the locking member 33 is also recessed to accommodate the spring 36.

A biasing means is further provided for the switch contact 21, comprising a pair of coil springs 40 carried by the spindle 28 and having ends 41 engaged with the spindle 35. The springs 40 are interconnected by a yoke portion 42 in the shape of a U, said yoke portion being accommodated in a notch 43 in the plate 26 to efiect a driving connection thereto.

It will be readily understood that, in accordance with the above construction, the switch contact 21 will normally be urged to a circuit-opening position as indicated by the broken outline 45 in Figure 2, and may be latched in circuit-closing position as indicated by the full outline, upon engagement of the cooperable shoulders 32 and 34 of the disk 26 and locking member 33 respectively.

Inaccordance withthepresent. invention I provide a novel, adjustable means responsive to inertia, by which the locking member 33may be actuated to release the switch member 21 for movement to the circuit-opening position 45. This means comprises. a two-armed lever 47 carried by a pivot 48 which is in turn supported in the guide portions 12 of the base plates 11. washers 39 may be provided to centralize the lever 47, as indicated in Figure l.

The lever 47 has a short arm 50 adapted to engage the extremity of the locking member 33 so as. to actuate the latter in a clockwise direction, to release the disk 26. Also, the lever- 47 has a long, weighted arm 52 carrying a weight 53. which is adjustable lengthwise of the arm 52, said arm responding to a decrease in rightto-left velocity of the entire switch mechanism by causing a counterclockwise swinging-of the lever 47. Thus, the weight 52 may shift the lever 47 to the position indicated by the broken outline 55 in Figure 2, thereby to cause release of the switch blade 21 for movement to circuit-opening position.

I provide on the guide portions 12 of the base plates 11a U-shaped strap 57 adapted to engage the long arm 52 of the lever 47 when the arm is in the dotted-line position shown, thereby to constitute a stop for the lever.

Also, in accordance with this invention, I provide an adjustable means for varying the action of the twoarmed lever 47 in response to a change in its velocity. This means comprises a pair of leaf spring detents 60 carried by the guide portions 12 of the base plate 11, said detents having inwardly-ofiset portions or ribs 61 engageable with the long arm 52 to yieldably hold the latter until a sufficient impact or force is experienced by it to cause the arm to bypass the detent springs. Adjustment of the detent action of the springs 60 is effected by set screws 62 carried by the guide portions 12 and engaging the springs adjacent the ribs 61 thereof. With this organization I am enabled to vary the response of the switch mechanism, thereby to adjust the latter for efifecting an opening of the circuit for all values of deceleration greater than a predetermined figure.

Further, in accordance with the invention, I provide 35 an auxiliary switch means by which a stand-by circuit may be activated upon opening of all of the remainder of the circuits of the conveyance, thereby to enable essential illumination to be had when this is necessary. The said auxiliary switch comprises a resilient switch arm 65 secured to the base by a terminal screw 66, said switch arm having a contact 67 engageable with a stationary contact arm 68 secured to the terminal post 24. An insulated actuator arm 70 is carried by the switch arm 67, for engagement by the switch blade 21 as shown in Figure 2, thereby to open the circuit between the terminals 24 and 66. However, upon the switch blade 21 being released, the resilient switch arm 65 will spring upward, causing the contact 67 thereof to engage the stationary switch arm 68, thereby to effect energization of the terminal 66 from the hot terminal 24 of the switch mechanism.

As shown in Figure 2, preferably the switch blade 21 is provided with a recess 72 in its trailing edge, and the latter has a straight portion 73 which becomes virtually parallel to the straight edge portions 74 of the switch contacts 14 and at the instant of separation of the blade 21, from said stationary contacts. Thus there is distributed any arcing which might occur at the separating edges, minimizing the effect of such arcing.

It will be readily understood from the foregoing that I have provided an extremely simple, yet efiective and reliable, inertia-actuated switch mechanism suitable for use in automobiles and other conveyances to open the electrical circuits thereof upon the conveyance suffering Spacing a sudden jar, jolt or stoppage, as from an accident. The present improved mechanism may be eas1ly and quickly adjusted by shifting the weight 53 along the long-lever arm 52, and by adjusting the tension of the leaf spring detents 60. The mechanism is relatively small, compact, composed of few, simple and economically fabrn cated parts, and may be readily mounted wherever a small amount of space is available. Moreover, it is not limited to the position illustrated wherein the weight 53 is uppermost, since other positions of the mechanism are possihle without adversely afiecting its operation.

Variations and modifications may be made within the scope of the claims, and portions of the improvements may be used without others.

I claim:

1. An inertia-operated electrical switch mechanism comprising a pair of cooperable switch contacts; means mounting one of said switch contacts for movement between a switch-closing position engaged with the other contact and a switch-opening position separated from I the other contact, said one switch contact being normally biased to switch-opening position; latch means including a shoulder on the movable switch contact, disposed at right angles to the line of movement thereof and a movable locking member movable into and out of the path of movement of said shoulder, for releasably holding said one switch contact in switch-closing position; and a twoarmed lever having one long arm and one short arm, disposed adjacent said locking member with its short lever arm engageable with the member to actuate the latter, the long arm of the lever being weighted and being movable in response to deceleration, thereby to enable the lever to actuate the locking member and effect release of the movable switch contact for switch-opening movement when the switch mechanism suflfers a given mechanical shock.

2. The invention as defined in claim 1 in which the means mounting the one switch contact constitutes a pivot, providing for arcuate movement of said contact.

3. The invention as defined in claim 2 in which there is a biasing means comprising a pair of coil springs disposed on opposite sides of the movable switch contact, for effecting automatic actuation of the latter.

4. The invention as defined in claim 3 in which the coil springs have straight, extended end portions and a yoke portion joining together said end portions, said yoke portion being drivingly connected to the said movable contact member.

5. The invention as defined in claim 2 in which there is a flat rotary member of insulating material, carrying the said movable switch contact and comprising the mounting means therefor.

5. The invention as defined in claim 2 in which the said other switch contact is of rectangular configuration, and in which the movable switch contact has a cut-back edge providing a portion which extends substantially parallel to the juxtaposed edge of said other contact at the moment of separation of the contacts.

7. The invention as defined in claim 1 in which there is an additional electric switch biased to closed position, and means maintaining said switch in open position in response to positioning of the said movable switch contact in switch-closing position.

8. The invention as defined in claim 7 in which the second switch means comprises a resilient contact arm and an insulated member secured to said arm and adapted to engage the said movable switch contact.

9. The invention as defined in claim l in which there is a weight carried by the long arm of the lever, said weight being shiftable closer to and further from the fulcrum of the lever to alter the efiect of deceleration on the lever.

10. The invention as defined in claim 1 in which the said other switch contact is stationary and in which there is an additional stationary switch contact rigid with and 5 insulated from said other contact, both said stationary switch contacts comprising substantially flat blades disposed broadside to each other in closely spaced relation, said movable switch contact comprising a blade adapted to be interposed between the said two stationary switch contacts.

11. The invention as defined in claim 1 in which the locking member comprises a lever the extremity of which is engaged by the said short lever arm.

12. The invention as defined in claim 1 in which there is a yieldable friction detent engageable with the long arm of the two-armed lever, to alter the effect of inertia on said lever.

13. The invention as defined in claim 1 in which there are parallel guides extending on opposite sides of the 15 2,778,896

6 long arm of the two-armed lever, and in which there is a strap connected to and extending across said guides, engageable with said long arm and providing a stop therefor.

References Cited in the file of this patent UNITED STATES PATENTS 470,773 Wurts Mar. 15, 1892 1,591,149 Waltamath July 6, 1926 2,627,709 Slebos Ian. 14, 1936 2,412,494 Cole Dec. 10, 1946 2,573,595 Oberg Oct. 30, 1951 2,585,749 Lorenzo et a1 Feb. 12, 1952 Tollefsen Jan. 22, 1957 

